It is known that medium and high voltage electric cables generally comprise a conductive core covered in an insulating layer, itself covered in a semiconductive screen in contact with metal shielding that is connected to ground and covered by an outer layer.
It is also known that when an electric cable is being connected to another electric cable or to a piece of equipment, or when an end of an electric cable is being made ready, it is necessary to strip the conductive core of the cable, and generally to cut the semiconductive screen back from the end of the insulating layer so as to avoid an electric arc forming between the conductive core which is taken to a high voltage and the semiconductive screen which is at ground potential.
In order to avoid dielectric stress appearing at the end of the semiconductive screen, it is then necessary to place a protective sleeve on the junction or on the end of the cable so as to come into contact with the end of the semiconductive screen, which protective sleeve includes a layer of material that is conductive, semiconductive, or stress-reducing.
The end of the semiconductive screen constitutes a step relative to the insulating layer of the cable, and the simplest solution for putting the conductive or semiconductive layer of the protective sleeve into connection with the end of the semiconductive screen consists in pressing the end of the sleeve against the end of the semiconductive screen. Nevertheless, whether at a cable junction or at a cable end, the protective sleeve is generally associated with other elements which are positioned relative to the end of the conductive core or the end of the insulating layer of the cable so that the protective sleeve can be brought into end-on contact with the semiconductive screen only on the condition of cutting away the semiconductive screen at a distance that is very accurate relative to the end of the conductive core or of the insulating layer, and that is difficult to achieve on site. In addition, pressing the end of the protective sleeve against the end of the semiconductive screen of the cable does not enable good sealing to be obtained between the coupling part and the cable.
In order to ensure a connection between the protective sleeve and the end of the semiconductive screen, it is therefore usual to provide for the protective sleeve to cover the end of the semiconductive screen over a distance that is several times the thickness of the semiconductive screen. To ensure good contact between the protective sleeve and the semiconductive screen of the cable, it is desirable for the protective sleeve to be made out of an elastic material having a diameter at rest that is slightly smaller than the outside diameter of the semiconductive screen of the cable.
Nevertheless, as mentioned above, the end of the semiconductive screen forms a step relative to the insulating layer, such that the end of the protective sleeve tends to come into abutment against said step while it is being put into place. To go past the step, it has been envisaged that a conical piece can be placed on the cable before the coupling part is put into place.
Nevertheless, that additional operation is a source of difficulty on a worksite.